Turning system and control information setting method
A turning system applied to a vehicle steering system, includes a turning unit, one or more processors, and a memory. The vehicle steering system has a structure in which a power transmission path between the turning unit and the steering unit steered by a driver is cut off. The one or more processors are configured to execute a mode setting process of setting a control mode in which the turning unit is operated to a setting mode or a normal control mode. The setting mode is a mode that is settable in an in-factory step before the turning unit is shipped to market. The normal control mode is a mode that is settable after the in-factory step is gone through. The mode setting process includes exclusively setting the setting mode or the normal control mode.
1 . A turning system applied to a vehicle steering system, comprising:
a turning unit that operates to turn a turning wheel of the vehicle, the vehicle steering system having a structure in which a power transmission path between the turning unit and a steering unit steered by a driver is cut off;
one or more processors that control the operation of the turning unit; and
a memory that stores control information that the one or more processors use to control the operation of the turning unit, wherein:
the one or more processors are configured to execute a mode setting process including setting a control mode in which the turning unit is operated to a setting mode or a normal control mode,
the setting mode is a mode that is settable in an in-factory step before the turning unit is shipped to market, and is a mode in which setting work for setting the control information in the memory by operating the turning unit is performed,
the normal control mode is a mode that is settable after the in-factory step is gone through, and is a mode in which the turning unit is controlled to operate using the control information,
the mode setting process includes exclusively setting the setting mode or the normal control mode,
the turning unit includes a turning shaft that operates to turn the turning wheel, and a turning-side motor that generates motive power for operating the turning shaft,
the one or more processors are configured to execute an in-factory turning process involved in performing the setting work, and the in-factory turning process includes a process of setting the control information in the memory by making the turning shaft perform at least one specified operation that is specified beforehand through driving of the turning-side motor,
the setting work includes work for setting a reference value that is a value linked to a mechanical state of the turning unit in the memory as the control information,
the reference value is a value indicating a moving-straight-forward state that is a turning state of the turning shaft when the vehicle moves straight forward,
the specified operations include a learning operation of moving the turning shaft to a motion limit in each of a first direction and a second direction,
the in-factory turning process includes acquiring, during the learning operation, a limit position in each of the first and second directions that is a position of the turning shaft at the motion limit in each of the first and second directions, and setting the reference value based on the limit position acquired in each of the first and second directions,
the in-factory turning process further includes setting, in the memory, completion information showing completion of setting of the reference value on a condition that the reference value has been set in the memory through the learning operation,
the mode setting process further includes setting the normal control mode when the completion information is set in the memory, and setting the setting mode when the completion information is not stored in the memory, and,
the completion information, once set in the memory, is retained when power to the turning system is turned on and off and is retained when a battery that serves as a power source for the turning system is replaced, such that the completion information is not deletable or initializable after being set in the memory, and
the in-factory turning process further includes determining that the turning shaft has reached the motion limit in each of the first direction and the second direction based on both:
a determination that a load on the turning-side motor has increased based on currents flowing through the tuming-side motor; and
a determination that the turning shaft is stationary based on an angular speed associated with a position of the turning shaft being smaller than an angular speed threshold value.
2 . The turning system according to claim 1 , wherein the in-factory turning process further includes performing a holding operation of holding a state of the turning shaft at start of the process and each time the specified operation is completed.
3 . A control information setting method for setting control information that is applied to a vehicle steering system having a structure in which a power transmission path between a steering unit that is steered by a driver and a turning unit that operates to turn a turning wheel of a vehicle is cut off, the control information being information that is stored in a memory belonging to a turning system configured to include the turning unit and that is used by one or more processors belonging to the turning system to control the operation of the turning unit,
the control information setting method comprising, by one or more processors, executing a mode setting process including setting a control mode in which the turning unit is operated to a setting mode or a normal control mode, and executing an in-factory turning process of operating the turning unit to perform setting work for setting the control information in the memory by operating the turning unit, in the setting mode that is settable in an in-factory step before the turning unit is shipped to market, wherein the normal control mode is a mode that is settable after the in-factory step is gone through, and is a mode in which the turning unit is controlled to operate using the control information, and the mode setting process includes exclusively setting the setting mode or the normal control mode, wherein:
the in-factory turning process includes setting the control information in the memory by making a turning shaft of the turning unit that operates to turn the turning wheel perform at least one specified operation that is specified beforehand through driving of a turning-side motor of the turning unit,
the setting work includes work for setting a reference value that is a value linked to a mechanical state of the turning unit in the memory as the control information,
the reference value is a value indicating a moving-straight-forward state that is a turning state of the turning shaft when the vehicle moves straight forward,
the specified operations include a learning operation of moving the turning shaft to a motion limit in each of a first direction and a second direction,
the in-factory turning process includes acquiring, during the learning operation, a limit position in each of the first and second directions that is a position of the turning shaft at the motion limit in each of the first and second directions, and setting the reference value based on the limit position acquired in each of the first and second directions,
the in-factory turning process further includes setting, in the memory, completion information showing completion of setting of the reference value on a condition that the reference value has been set in the memory through the learning operation,
the mode setting process further includes setting the normal control mode when the completion information is set in the memory, and setting the setting mode when the completion information is not stored in the memory, and,
the completion information, once set in the memory, is retained when power to the turning system is turned on and off and is retained when a battery that serves as a power source for the turning system is replaced, such that the completion information is not deletable or initializable after being set in the memory, and
the in-factory turning process further includes determining that the turning shaft has reached the motion limit in each of the first direction and the second direction based on both:
a determination that a load on the turning-side motor has increased based on currents flowing through the turning-side motor; and
a determination that the turning shaft is stationary based on an angular speed associated with a position of the turning shaft being smaller than an angular speed threshold value.
4 . The turning system according to claim 1 , wherein the in-factory turning process further includes:
calculating a midpoint value based on the limit position acquired in each of the first and second directions;
determining whether the midpoint value is within a predetermined range between a lower threshold value and an upper threshold value; and
repeating the learning operation when the midpoint value is determined not to be within the predetermined range, and setting the reference value based on the midpoint value when the midpoint value is determined to be within the predetermined range.